Although fat is an indispensable part of our diets we tend to have too much fat as part of our regular diet. Excess fat intake has been identified as a major factor in ailments of civilized societies; the American Heart Association recommends that no more than 30% of total caloric intake be derived from fat to help minimize such health problems as cardiovascular disease. Not only is fat thought to be a specific contributing factor in certain increasingly common ailments, but it also contributes to an excessive calorie intake common in the United States as well as in other countries. With increasing recognition of this fact in recent years has come increasing research and development efforts to produce foods with lower calories through reduction of their fat content. The challenge is considerable, for the quest is to develop fat-free or reduced fat foods, such as meats and meat products, while retaining the characteristics of full-fat products. Thus, one desires to develop a meat product with the texture and organoleptic properties of meat, including localized tenderness, juiciness and lubricity and which undergoes "rendering" upon heating, by substituting the animal fat normally present with a product which is inexpensive, has few or no calories, is odorless, and which can be incorporated into meat like animal fat.
The concept of localized tenderness, juiciness, and lubricity is important in understanding the organoleptic and textural properties of meat. Animal fat occurs in pockets within the lean portion of meats, and if absent the resulting cooked meat would be very tough and rubbery, as the meat proteins would be able to form a very tightly bound network of interlinked molecules. The animal fat present serves several functions in tenderizing the protein structure. Specifically, the space taken up by the animal fat piece physically creates a region where the proteins cannot link to each other tightly. In addition, during cooking the triglyceride portion of the animal fat renders out of the pocket and penetrates the surrounding tissues, providing further interference with the formation of tightly bound proteins in the area adjacent to the pocket, leading to localized tenderness. It follows that, e.g., a hamburger patty is homogeneous in neither its composition nor its texture. During mastication the meat patty structure breaks down, first along those areas adjacent to a particle of fat, then on the rubbery lean sections.
If one merely added a triglyceride to, say, 95% lean ground meat in a proportion to yield a 70% lean product the latter no longer will have pockets of fat, but instead the fat will be distributed more homogeneously and will not manifest the local functionality as described above. In particular, the meat will be more crumbly and, if cooked to well doneness, will be friable and no longer rubbery like a regular 70% lean patty. Therefore, to deliver equivalent sensory properties to lean meats, a fat mimetic also must take into account the phenomenon of localized tenderization as well as lubricity, bite, and juiciness.
Fat replacers can arbitrarily be divided into the two categories of fat substitutes and fat mimetics. Fat substitutes, sometimes referred to as "synthetic fats", are materials which resemble natural fats both chemically and functionally, that is, they are chemically related to the triglycerides constituting fats and they function like fats even as to such properties as frying. Such materials are represented by malonate esters (U.S. Pat. No. 4,582,927), sucrose polyesters (U.S. Pat. No. 3,600,186), esterified propoxylated glycerols (U.S. Pat. No. 3,793,380; EP254,547), alpha-acylated glycerides (U.S. Pat. No. 4,582,715), alkyl glycoside polyesters (U.S. Pat. No. 4,942,054) and polyglycerol fatty acids (U.S. Pat. No. 3,637,774). It is essential to recognize that the term "fat substitutes" as used here denotes a class of esters which perforce are chemically analogous to natural fats and oils, and whose functional behaviour also is quite similar to the natural fats and oils. As will be better appreciated from the description within, our invention differs fundamentally from those incorporating "fat substitutes" in that the problem faced is that of making a product fat-like without adding a fat or oil, or any other material chemically analogous to a fat or oil.
Fat mimetics resemble natural fats only functionally and represent a diverse class chemically quite different from the triglycerides of natural fats. Fat mimetics include such materials as starch hydrolysate products, including maltodextrins, microparticulates, hydrocolloids, hemicelluloses, and beta-glucans, among other materials. See "Development of Low Fat, Low Caloric Food Products", given at East Brunswick, N.J., Dec. 11, 1991. For example, particles ranging in size from 0.1-3.0 microns are perceived as creamy, especially when the particles are spherical, irrespective of the nature of the particles. Thus, microparticulates suitable as fat mimetics include proteins, (e.g., Simplesse.TM., a microparticulated protein of uniform spherical particles about 1 micron in diameter) as well as cellulose (microcrystalline cellulose, Avicel.TM. and microfibrillated cellulose) and carbohydrate crystallites (Stellar.TM.). Of particular interest to us here are hydrocolloids such as alginates, carrageenans, and agar and the partially hydrolyzed starches, especially low dextrose equivalent dextrin.
Carrageenan and other gums, especially seaweed extracts and locust bean gum, have a high binding capacity for water, a property which has led to their introduction into meats as an animal fat replacement. Such materials form a gel with water which is readily incorporated into meat products. For example, carrageenan either alone or in combination with non-meat proteins and starches has been used as an animal fat replacer in a variety of meat products, especially frankfurters, beef patties, and low-fat sausages. See, for example, L. Hoegh, "Food Ingredients Europe Conference Proceedings", 1991, pages 305-10; H. W. Hoogenkamp, idem., 311-314. A commercial product of carrageenan, water, and flavors (CarraFat.TM.) has been touted as an animal fat-replacement "wonder product".
Sodium alginate is another gel-forming seaweed extract which differs from carrageenan in that gel formation occurs only in the presence of divalent cations such as calcium or magnesium. Recently a process for preparing alginate gel-structured meat products has been described in U.S. Pat. No. 4,603,054. Although meat products based on carrageenan and alginated gels alone form an advance in the art, especially in the context of animal fat reduction, the texture and mouth feel of the resulting product is not equivalent to a full-fat product, and the meat does not behave as does a full-fat product upon cooking.
Recently partially hydrolyzed starches, such as various maltodextrins, have found increasing use as fat mimetics because of their gel-forming properties which contribute some of the same sensory characteristics as do fats. Maltodextrins from such diverse sources as rice, oats, tapioca and potatoes have been used as fat replacers and seem to show exceptional flavor release. For example, oat maltodextrin containing 1-12% beta-glucan soluble fiber in combination with water (1:3) forms a thermoreversible gel having a fat-like mouth feel and a creamy texture. J. F. Kacher, "Food Ingredients Europe Conference Proceedings", 1991, pages 168-172. Low DE (dextrose equivalent) potato starch maltodextrins (DE .ltoreq.5) have been reported as partial fat replacements in salad dressings and margarine. V. De Coninck and J. Vanhemelrijck, idem., 173-7. Although the gel-forming properties of maltodextrin were required in the foregoing applications, U.S. Pat. No. 4,536,408 utilizes a quite different approach where starch hydrolysates of DE.ltoreq.25 are used to promote a water-in-oil emulsion with a natural fat and gel formation of the starch hydrolysate must be avoided.
Our approach to the design of an animal fat replacement product differs substantially from that of the prior art even though a superficial examination may not reveal the profound underlying difference. What we have done is to structure water to behave like an animal fat in meat. In particular, fats in meats are present as a triglyceride in a collagen network, and the prior art appears to have completely ignored the network or matrix aspect of meat fat. In contrast, we believe the network is an essential aspect of fat functionality in meats which needs to be duplicated in an animal fat replacement product to afford a material with the proper texture, lubricity, and juiciness. Our product is a combination of a maltodextrin, optionally starch, and water entrapped in an alginate matrix. The product itself is a white solid which looks and feels like animal fat when cold, and which can be combined with meat in the same manner as is animal fat. When heated the maltodextrin-water gel melts, leaks from the matrix, and tenderizes the meat while leaving behind the alginate network which can be clear, opaque, or colored, which has a rubbery texture, and which chews like animal fat. The result is a meat which chews and feels to the bite the same as does a full-fatter meat product. An advantage of our product is that liquid is released upon heating analogous to fat rendering, hence the meat is locally tenderized and behaves similarly to a full-fat product upon cooking. Another advantage of our product is that it is an excellent delivery system for additional ingredients, especially flavoring additives.